1. Field
Aspects of one or more embodiments according to the present invention relate to an organic light-emitting display device and a method of manufacturing the same.
2. Description of the Related Art
The rapid development of the information and technology (IT) industry has dramatically increased the use of display devices. Recently, there have been demands for display devices that are lightweight and thin, consume low power, and provide high resolution. To meet these demands, liquid crystal displays or organic light-emitting displays using organic light-emitting characteristics are being developed.
Organic light-emitting displays, which are next-generation display devices having a self light-emitting characteristic, have better characteristics than liquid crystal displays in terms of viewing angle, contrast, response speed, and power consumption, and can be manufactured to be thin and lightweight since a backlight is not used.
An organic light-emitting display includes a substrate having a pixel region and a non-pixel region, and a container (or another substrate) which is placed to face the substrate for encapsulation and is attached to the substrate by a sealant such as an epoxy. In the pixel region of the substrate, a plurality of organic light-emitting devices are arranged in a matrix pattern between scan lines and data lines to form pixels. In the non-pixel region, there are the scan lines and the data lines extending from the pixel region, power source supply lines for operating the organic light-emitting devices, and a scan driver and a data driver for processing signals received from an external source via input pads, and providing the processed signals to the scan lines and the data lines, respectively.
Hereinafter, the structure of a conventional organic light-emitting display device and a method of manufacturing the conventional organic light-emitting display device will be described with reference to FIGS. 1A, 1B, and 2. FIGS. 1A and 1B are cross-sectional views of a conventional organic light-emitting display device. FIG. 2 is a flowchart illustrating a conventional method of manufacturing an organic light-emitting display device.
Referring to FIG. 1A, the conventional organic light-emitting display device includes gate electrodes GATE formed at a transistor region TFT and a capacitor region Cst of a substrate, a gate insulating film formed on the gate electrodes GATE to insulate the gate electrode GATE of the transistor region TFT from an active layer OXIDE which is made of an oxide, and the active layer OXIDE formed above the gate electrode GATE of the transistor region TFT.
The active layer OXIDE made of an oxide may be formed by the same or similar process as an active layer made of amorphous silicon. The active layer OXIDE made of an oxide enables a thin-film transistor to be driven with precision and to operate several tens of times faster than a conventional active layer made of polysilicon does. However, the oxide is sensitive to the air.
For this reason, as shown in FIG. 1A, an etch stop layer ESL is additionally formed on the active layer OXIDE. Then, source/drain electrodes S/D which are connected to the active layer OXIDE via contact holes formed at the etch stop layer ESL, a passivation film PSV, a pixel electrode PXL_E, and a pixel defining layer PDL are sequentially formed.
In this structure, the gate electrodes GATE, the active layer OXIDE, and the source/drain electrode S/D are sequentially stacked from the bottom. Thus, as shown in FIG. 1B, this structure inevitably produces an overlap area OL between the source/drain electrodes S/D and the gate electrode GATE at the transistor region TFT.
This is because the source/drain electrodes S/D of the transistor region TFT are formed on the oxide active layer OXIDE and are connected to the oxide active layer OXIDE by the contact holes.
Due to this structure, undesirable parasitic capacitance is generated between the gate electrode GATE and the source/drain electrodes S/D of the transistor region TFT, thereby deteriorating the performance of a transistor that constitutes the conventional organic light-emitting display device.
Referring to FIG. 2, in a conventional method of manufacturing an organic light-emitting display device, gate electrodes, an active layer, an etch stop layer, source/drain electrodes, a passivation film, a pixel electrode, and a pixel defining layer are sequentially formed by patterning processes using patterning masks (operations S1 through S7).
That is, each operation uses at least one mask to form a photoresist film used in a partial etching process for patterning. Accordingly, the total number of processes is increased, which, in turn, raises manufacturing costs. This is because when an active layer is formed using an oxide that is sensitive to the air, an etch stop layer is additionally used to protect the active layer.
In this regard, an organic light-emitting display device which can be mass-produced in a simplified process with an active layer formed of an oxide and a method of manufacturing the organic light-emitting display device are desired.